The properties of MMC cards are disclosed e.g. in the MMC specification “MultiMediaCard System Specification Version 4.1 Official Release (c) April 2005 MMCA”.
Presently, the memory card specification does not describe partitioning or other details about the internal functionalities of memory cards. Therefore, the functionality of internal firmware in case of wear leveling, garbage collection, data compaction, bad block management and other memory technology related issues, which are required for proper card functionality, are card specific and cannot be controlled by host.
The flash memory layout of modern mobile terminals has usually multiple partitions. These partitions are usually binary partitions (read-only) and read-write partitions such as known from hard discs. The read-only partitions may be updated only a few times in device lifetime and the probability of their corruption must be very low. The read-write partitions are more heavily used but also there data consistency is very important. There may also be some read-write partitions that contain data needed for device operation (has to be stored highly secured way).
In existing memory cards/modules and memory card specification partitions are not defined (i.e. all data in card can be said to be located in same partition). This means higher risk of data corruption for example during sudden power-cut-off (power supply interruption) situations (if at the same time erase or write operation internally in card going on) and results in lower data security.
Even though data security of data stored in currently used storage card is not yet a highly relevant topic it should be considered as always desirable to increase the data security of storage media.